libuuid

8.16

libuuid🔗ℹ

Interface to the libuuid library usable to generate high-quality UUIDs.

package: libuuid

procedure
(uuid-generate) → string?

Generate new universally unique identifier using /dev/urandom, if available. If it is not available, use current time, local ethernet MAC address and random data from a pseudo-random generator.

Examples:

> (uuid-generate)
"bd60d5ef-d171-44c1-b137-94d84f8ed6a9"
> (uuid-generate)
"0eee90c3-5a45-412f-9362-9679a6f4e046"

procedure
(uuid-generate/random) → string?

When /dev/urandom is available, same as uuid-generate, but fails back to a pseudo-random generator only.

Can be used to prevent any chance of host’s MAC address leaking, at the cost of slightly higher chance of generating non-unique identifiers if the worst-case situation arises on multiple hosts.

Examples:

> (uuid-generate/random)
"a02918ae-02af-43bf-b441-0ccb322d08e5"
> (uuid-generate/random)
"c37c1492-399c-4d3a-b3b9-685d924c1915"

procedure
(uuid-generate/time) → string?

Same as uuid-generate when the /dev/urandom is missing.

Could potentially produce non-uniqueue identifiers if used concurrently so if you do not absolutely need sequential identifiers, stick with the generic (and safe) uuid-generate function above.

Examples:

> (uuid-generate/time)
"d163e98c-f630-11ef-83a5-2ba583640f6f"
> (uuid-generate/time)
"d163fbe8-f630-11ef-83a5-2ba583640f6f"